Method for controlled lubricant delivery when molding tacky materials

ABSTRACT

The present invention provides a lubricant-impregnated porous substrate. The lubricant-impregnated porous substrate may be used to deliver lubricant as needed to gloves or other surface contacting a tacky resin material during molding or forming of the tacky material. In particular, the lubricant-impregnated porous substrate may be used to lubricate gloves during molding and forming of orthopedic casting materials. The lubricant-impregnated porous substrate may be packaged one or more in a container, and the lubricant-impregnated porous substrate may also be packaged as a kit with the orthopedic casting material.

FIELD OF THE INVENTION

The present invention relates to a method for controlled, on-demandlubricant delivery to gloves or other surfaces, the lubricant providingan outer layer on said gloves or surfaces to allow touching or handlingof tacky materials without sticking. In a particularly preferredapplication, the method provides for on demand lubrication of glovesduring forming of tacky orthopedic casting materials about a body partprior to setting of the cast. The present invention further relates to acast kit including at least one flexible substrate impregnated with thelubricant.

The present invention further relates to porous articles that areimpregnated with a lubricant and packages including one or more of sucharticles.

BACKGROUND AND SUMMARY OF THE INVENTION

In many instances it is necessary or desirable to form or mold tackymaterials by hand, generally using protective gloves. For example, tackyresinous materials may be molded by hand into certain forms or shapes.The resinous material may have a resinous matrix, whether filled withother materials or not, or may be a resin impregnated into a poroussubstrate. Practical uses of such materials include knitted or wovenfiberglass impregnated with a tacky material that may be used to repairwater pipes or boats, tacky epoxy materials that may be used inrepairing mufflers and automobile bodies, tacky epoxy resin wraps thatmay be used to repair poles such as utility poles like telephone poles,and the tacky, curable materials that are widely used in makingorthopedic casts and splints. In each of these cases a lubricant may beapplied to protective gloves to prevent the gloves from sticking to thetacky resinous material.

In forming orthopedic casts and splints, in particular, it has becomenecessary to devise a simple and versatile means of lubricant deliveryto a glove. Casts and splints are widely used for immobilizing a bodymember, for example to allow a broken bone to heal properly. Plaster ofparis casts have recently been largely replaced in many applications byorthopedic bandages or sheets impregnated with tacky synthetic resinmixtures. The synthetic resins used in combination with certain knittedor woven substrates offer a number of advantages over the old plaster ofparis materials. Casts made from the synthetic materials are lighter,stronger, harden more quickly, allow for better air circulation, and arenot water sensitive.

Among the synthetic resin compositions used to prepare casting materialsare water-activated or water-curable synthetic resin compositions andthermoplastic resin compositions. Like the old plaster casting material,the water-activated or water-curable synthetic resin impregnatedbandages or sheets, which may also be called tapes, are wetted beforeapplication to the body member. The water begins the curing reactionthat hardens the cast. Other compositions for casting materials usesynthetic resin compositions employing different kinds of curingmechanisms, for example crosslinking through unsaturation.

The synthetic resin orthopedic sheets being used, however, are moredifficult to mold about the body member than the old plaster of pariscasting sheets due to the tackiness of the resin. This problem may beovercome by interjecting a lubricant between the tacky bandage and thesurface, usually a gloved hand, that is being used to mold the cast.

Various means of delivering the lubricant to the glove have beensuggested. A mixture of water, sorbitol, mineral oil, and silicone fluidis commercially available from 3M Co., St. Paul, Minn., under thetradename Cast Cream for application to the gloves after wrapping thecast but before molding the cast. Richard et al. disclose a lubricatedglove for applying orthopedic cast bandage in EP 712 618. A hydrophiliclubricant is added to a flexible elastic glove material. In U.S. Pat.No. 5,438,709, Green et al. disclose lubricated gloved formed from aelastomer, preferably a latex, with a lubricating polyvinyl alcoholexternal coating. The PVA may be thickened with, e.g., rhamsan gum. Theexternal coating may be applied by dipping the glove in a solution ofthe lubricant, followed by drying the coating. In U.S. Pat. No.5,439,439, Green et al. disclose a similar lubricated glove coated withpolyvinylpyrrolidone. These gloves are believed to be difficult tomanufacture reproducibly. A further drawback to these coated gloves isthat the person molding the cast has no control over the amount oflubricant applied to the gloves.

Another approach that has been used is to "prelubricate" the castingsheet or tape, i.e., to provide a lubricant to a part of the castingsheet that is impregnated with the tacky resin, as opposed to thecurrent method of applying the lubricant to the gloves. Scholz et al.disclose in U.S. Pat. Nos. 4,667,661 and 4,774,937 curable resin-coatedsheets prelubricated with a hydrophilic lubricant. The lubricant ispresent in an amount sufficient to reduce the kinetic coefficient offriction of the sheet surface to less than 1.2. Dull et al., U.S. Pat.No. 4,937,146, impregnate a tape with a mixture of a resin and anon-polar hydrophobic lubricant. The mixture is unstable to the extentthat at least part of the lubricant migrates to the surface of thecoated sheet to impart low surface tack. Prelubricating all surfaces ofthe sheets, however, has the drawback that more lubricant is used thanis necessary or desirable, and there is no control over the amount ortime of application. For instance, it may be desirable to have thewrapped layer stick to one another without slipping and to have the endof the sheet or bandage stick to the surface of the casting sheet wrapin order to terminate the application of the sheet. Moreover,incorporating certain lubricants, such as mineral oil, into the curableresin composition may result in longer set time due to the dilution ofthe resin curing sites. It is also necessary to avoid a lubricant thatwould react with the casting resin during storage, as reaction couldharden the resin and make the product unusable.

A water-soluble liner layer for casting sheets is disclosed by Scholz etal., WO 94/23769. The liner prevents pooling of resin from out of thecasting sheet roll and prevents adhesion of adjacent layers of the roll.The reference discloses that the liner dissolves when the casting sheetis immersed in water to expose the casting sheet. The dissolved linermay also lubricate the casting sheet. This method of lubricating thewhole length of the casting sheet, however, is subject to the sameshortcomings as the pre-lubricating method.

The present invention provides an improved means of delivering a desiredamount of lubricant to selected sites on the gloves one or more timeswhen working with tacky materials, in particular tacky resins andpolymers, and to articles used in such methods. In one embodiment, thepresent invention concerns delivering lubricant to gloves during formingan orthopedic cast to prevent the gloves from sticking to the castingmaterial, as well as an orthopedic casting kit for carrying out themethod. A lubricant-impregnated porous substrate and a packagecontaining one or more such substrates is also provided.

In one method of the present invention, a porous substrate isimpregnated with a lubricant. The impregnated substrate is then used todeliver lubricant to the gloves of the person forming the tacky resin orcast material to prevent the gloves from sticking to the resin materialor cast tape during application and molding of the material. The presentmethod offers a number of advantages over prior methods. First, only asmuch lubricant as is necessary is applied to the gloves and the castbeing molded. Accordingly, a certain amount of tackiness may bemaintained if desirable. Secondly, because the lubricant is not admixedwith the curable composition, or applied to the cast sheet or tape forthe purpose of significantly affecting its tackiness, the lubricant maybe selected from a wide variety of materials, including materials thatmight be reactive toward the curable composition of the casting sheet orother tacky material being formed, or that would otherwise affect shelflife or performance. In addition, the lubricant may be reapplied to thegloves as desired during application and molding of the cast material,or while working with other tacky materials. Thus, the level oftackiness can be controlled according to the preference of theindividual casting technician. Finally, the lubricant need not behydrophilic, as is required in many of the prior methods describedabove.

DETAILED DESCRIPTION

The invention provides an article that is a porous substrate impregnatedwith a lubricant. The impregnated substrate is used to lubricate glovesbefore handling tacky materials, such as tacky resin or polymercompositions, so that the tacky materials may be worked with and formedwithout having the gloves, or other surface used for the handling, stickto the tacky material. It is our intention for the scope of theinvention to include in its methods and combinations all tackymaterials, while herein after the description may focus on orthopediccasting materials.

The lubricant impregnated porous substrate is contacted with the surfaceof the glove, for example by rubbing the lubricant impregnated poroussubstrate on the desired surface of the glove, to deliver lubricant tothe glove one or more times. One or both of the lubricant impregnatedporous substrate or gloves may optionally be wetted with water orimmersed in water before transferring the lubricant to the glove, andthis step may be preferred when the lubricant is water soluble or waterdispersible. In some cases, the lubricant impregnated substrate may beimmersed in water or wetted before being used one or more times todeliver lubricant as needed to the gloves.

The porous substrate that is impregnated with a lubricant should becapable of delivering the lubricant to the desired surfaces, preferablyin a controlled fashion. Preferably, the porous substrate has at leastsome flexibility or deformability that aids in lubricant delivery. It isparticularly preferred for the porous substrate impregnated withlubricant to be a film, a foam, or a sponge; or a textile or fabricarticle, including articles that may be described as cloths, sheets,tapes, towelettes, pads, or the like. In a more preferred embodiment,the porous substrate is a cloth, sheet, towelette, pad, or sponge.

In a preferred embodiment, the porous substrate is a towelette, piece offabric, or similar thin article with holes or pores to hold, and thenrelease, the lubricant. The porous substrate may have a broad range ofsizes, but it is preferred to have the porous substrate be of a sizethat is large enough to deliver a sufficient amount of lubricant butsmall enough to be easily handled. For example, the porous substrate mayhave dimensions of a thickness of from about 0.2 millimeter to about 10centimeters, a length of from about 1 centimeter to about one meter, anda width of from about 1 centimeter to about one meter. Preferreddimensions in the case of a sheet or towelette are thicknesses of up toabout 3 centimeters, preferably thickness of less than 2.5 cm,particularly from about 0.02 to about 1.5 centimeters; lengths of up toabout 100 centimeters, particularly from about 5 to about 50centimeters; and widths of up to about 100 centimeters, particularlyfrom about 5 centimeters to about 50 centimeters. It will be appreciatedby the skilled artisan that the physical dimensions of the poroussubstrate will depend upon its nature and the particular application.

In another embodiment, the porous substrate is in the form of acontinuous web of sheets connected in end-to-end relationship separatedby a scored line or perforations, much like paper toweling.

The porous substrate preferably comprises a knitted, woven, or nonwoventextile or fabric. The weight of the fabric is not particularlycritical, and may range, for example, from about 1 ounce per square yardto about 15 ounces per square yard. Suitable materials include, withoutlimitation, cotton fabric or cotton felt, ramie, jute, silk, wool,linen, rayon, acetate, triacetate, polyamides such as nylons, acrylics,polyester brushed tricot, and copolymers such as spandex (apolyester-polyurethane), as well as blends of these. Among preferredfabrics are 100% polyester brushed tricot and non-cellulosic paper.Other suitable articles include, without limitation, natural andsynthetic sponges, gauze pads of natural or synthetic fibers, and padsfilled with absorbent fibers, yarns, or other materials such as cotton,dacron, or fiberfill, preferably those pads having surfaces non-reactivetoward the water-curable resin. The porous substrate is preferablystrong enough to be handled in and out of water, as for example duringthe formation of the orthopedic cast, without excessive tearing ordisintegration.

The porous substrate is impregnated with at least one lubricatingmaterial. The amount of lubricant that is impregnated into the poroussubstrate is at least about 20%, preferably at least about 50%, morepreferably at least about 100%, and still more preferably at least about400% by weight, based on the weight of the porous substrate. Thelubricant-impregnated porous substrate article of the resent inventionis at least about 16% by weight lubricant, preferably at least about 33%by weight lubricant, more preferably at least about 50% by weightlubricant, and still more preferably at least about 80% by weightlubricant, based on the weight of the article.

The lubricant that is used to impregnate the porous substrate may beselected from a wide variety of lubricating materials. The lubricant iseither not reactive with the tacky resin or casting material or else theimpregnated porous substrate is separated from the casting sheet duringstorage in order to prevent any reaction with the resin of the castingsheet. One means of preventing such contact is by a barrier layerinterposed between the impregnated porous substrate and the curableresin impregnated casting sheet in a casting kit containing both items.Even when there is no barrier layer between the lubricant impregnatedmaterial and the curable-resin coated sheet, the lubricant is notdeposited onto the surface of the casting material in any appreciableamount or for any appreciable length during storage or at any pointprior to use, and the tackiness of the cast sheet remains essentiallyunchanged in the packaged article.

Examples of useful lubricants include, without limitation, water solubleor hydrophilic polymers such as polyethylene oxide, polyethylene oxideblock copolymers such as copolymers of ethylene oxide and propyleneoxide, polyvinyl alcohol, hydroxyethyl cellulose, carboxymethylcellulose, acrylamide-based polymers, and polyvinylpyrrolidone;surfactants such as polyethoxylated fatty alcohols and their salts,including sodium laureth sulfate ethoxylate; fatty amides; fatty acidsand their salts, such as metallic or organic stearates; lecithin-basedlubricants; waxes, such as carnuba wax and paraffin; sulfonated orcarboxylated polymers, such as sulfonated or carboxylated polyurethanes;hydrophilic, oligomeric diols, such as the reaction product ofpolyethylene oxide glycol with dimethyl sodium sulfoisophthalate in a2:1 molar ratio; hydrophobic lubricants and oils, such as mineral oils,petrolatum, vegetable oils, and derivatives thereof; synthetic andnatural motor oils; silicones and other fluids, oils, and greases, suchas polydimethylsiloxanes, polymethylphenylsiloxanes, andpolydiphenylsiloxanes, especially those having viscosities of betweenabout 100 and 100,000 centistokes; fluorinated greases, and mixtures ofany of these materials. Mixtures may also be employed. In a preferredembodiment, the lubricant is a mixture of an oil and a surfactant.Silicone oils or mixtures of silicone oils and surfactants areparticularly preferred. The silicone oil may be up to about 100% byweight, preferably from about 80 to about 100% by weight, and morepreferably from about 90 to about 99% by weight of the mixture.

The impregnating lubricant mixture may include other ingredients, suchas stabilizers, thickening agents, pigments or colorants, dyes, organicsolvents or cosolvents, and so on.

The lubricant impregnated porous articles may be packaged, with one ormore article per package or container, for storage before use. Theinvention further provides a container comprising one or more of thelubricant-impregnated porous substrates. In the case of a volatilelubricant, the container may comprise a closed or, preferably, sealedpackage capable of preventing evaporation of the lubricant, wherein thepackage contains one or more of the lubricant-impregnated poroussubstrate or substrates.

Packaging suitable for containing lubricant impregnated sheets,towelettes, pads, rolls, sponges, and so on are known. For example, apackage dispenser for dispensing sheets or towelettes of the inventionmay comprise a container, said container having a cavity, and saidcavity having therein a plurality of the sheets or towelettes. Thecontainer may have an opening on one end through which said sheets ortowelettes may be taken or pulled. The container may have one or moreleak-proof layers, such as a hermetic seal. The seal may be made of aflexible material or of a deformable plastic coated foil or uncoatedfoil. The container may be made of either a rigid or a flexiblematerial, or a combination of rigid and flexible materials. For example,the container may be formed from a rigid plastic or semi-rigid plasticsuch as a polyethylene, polypropylene, polyethylene terephthalate, orfrom a more flexible material such as a composite film.

Multiple articles of the invention may be placed within the container inrandom or ordered configurations. Thus, in the case of pads or sponges,the articles may be packed randomly in whatever number the cavityallows, while sheets, towelettes, or similar articles may be ordered instacks or rolls in the containers.

The container may contain, for example, a continuous web of material incompacted form having sheets connected in end-to-end relationshipseparated by scored lines or perforations, from which the respectivesheets can be readily dispensed, one at a time. Such a container mayinclude a body containing the continuous web; a closure for thecontainer; and a dispensing opening through which the web is withdrawnand a sheet of the web separated at the scored line or perforations.Preferably, as each sheet is pulled out and separated, the next sheet isexposed above the dispensing opening. The web may be in the form of aroll, and the web may be drawn for dispensing from the center of theroll. Alternatively, the sheets or towelettes may be stackedface-to-face in the container. In yet another embodiment, the sheets ortowelettes may be partially overlapped or stacked as an interfoldedarray so that when one is withdrawn from the container, the next in thestack is presented in a graspable position.

In general, containers or packages of the kind commercially availablefor dispensing tissues, paper, towelettes, and similar items can be useda package for the lubricant impregnated porous substrates of theinvention having similar shapes or dimensions.

Generally, the lubricant-impregnated porous substrate of the inventionis used to apply lubricant to gloves. Suitable gloves that may be usedto handle the tacky material include gloves made from polyvinylchloride, vinyl, latex, butyl rubber, or other such elastomericmaterials. The gloves should be substantially nonporous to the lubricantso that the lubricant is not absorbed by the glove but instead remains,at least for the most part, on the surface of the glove.

In one preferred embodiment, the lubricant-impregnated porous substrateis used with a curable-resin impregnated sheet. The curable resin may beany of the kind known in the art, including water-curable, UV-curable,EB-curable, heat-setting, and air-dry (oxygen-curing) materials. In aparticularly preferred embodiment, the curable-resin impregnated sheetis an orthopedic casting or splinting material or tape, preferablyimpregnated with a water-curable resin. An orthopedic cast is formed bytransferring lubricant from a lubricant-impregnated porous substrate toa glove on the hand of the person forming the cast. The lubricated gloveis used to apply and form a casting material around a body member.Lubricant may be reapplied to the glove as desired during theapplication and forming of the cast. After the casting material has beenapplied, it is allowed to harden to form an orthopedic cast around thebody member.

The utility of the of lubricant-impregnated article of the inventiondoes not depend upon the curing mechanism of the tacky material,although the particular lubricant may be chosen with the character ofthe tacky material in mind. For instance, hydroxyl-functional lubricantsmay be avoided if the tacky material is reactive with hydroxyl groups.In one preferred embodiment, the tacky material is a casting sheet ortape impregnated with a water-activated curable composition. The curablecomposition comprises, for example, a polymerizable or crosslinkingmaterial and may in addition comprise a catalyst or initiator forpromoting the desired reaction.

The sheet substrate that is impregnated with the curable resin ispreferably an open-weave structure of a fibrous material. Examples ofsuitable porous material for the casting sheet include, withoutlimitation, woven, knit, and non-woven fabrics of natural and/orsynthetic fibers. In a preferred embodiment, the casting materialcomprises knit fiberglass fabrics, polyester fabrics, acrylic fabrics,or extensible materials such as are described in U.S. Pat. Nos.4,609,578 and 4,668,563, both of which are incorporated herein byreference. Useful fiberglass-based materials include, withoutlimitation, those disclosed in U.S. Pat. Nos. 4,323,061; 3,686,725;3,787,272; 3,882,857; 4,376,438; and 4,411,262, the disclosure of eachbeing incorporated herein by reference. A preferred embodiment employs aknitted fabric that combines a high modulus fiber, such as a fiberglass,polyaramide, or polyethylene fiber, with an elastomeric, highlyextensible fiber, such as a natural rubber, spandex (a polyurethane),polyisoprene, polybutadiene, diene copolymers, acrylonitrile copolymers,EPM, or EPDM fiber. Casts using substrates that are extensible may beeasier to conform to the body of the patient.

The substrate sheet material may be coated with a substance formodifying the fibers of the substrate prior to impregnation with thecurable resin mixture. If used, the modifying substance preferably doesnot interfere with the impregnation or detrimentally affect theperformance of the curable resin mixture. One example of a modifyingsubstance is a low modulus binder that may be applied to prevent orreduce fraying of cut ends of the substrate, as is disclosed in U.S.Pat. No. 4,800,872, incorporated herein by reference.

The casting tape, when impregnated with the curable resin, preferablyhas at least some flexibility. The impregnated casting material shouldhave sufficient flexibility so that it can be molded about a limbwithout excessive pressure to form need to support and/or protect thelimb. The casting material is at least partially impregnated with acurable resin.

The curable resin of the casting material may be any curable resin thatsatisfies the functional requirements of an orthopedic cast. Theresin-impregnated sheet should be pliable before cure, but should uponcure become rigid and strong to support the loads and stresses to whichthe cast may be subjected by the activities of the patient. Thehardening should take place fairly rapidly once curing has beeninitiated, preferably attaining weight-bearing strength within about 30minutes. The curable resin is selected from materials that preferably donot emit significant amounts of toxic by-products during curing thatmight be harmful to either the patient or the person applying the cast.The curable resin also is preferably non-irritating to the skin andshould not generate an excessive amount of heat during curing that mightcause discomfort or burns to the underlying skin.

The curable resin may cure by a variety of mechanisms. The cure reactionshould not generate an amount of heat that would cause discomfort orburns to exposed skin. Among known curable resin systems used for castsare catalyzed polyurethane prepolymers and water-reactive alkoxysilaneterminated resins.

The curable resin is preferably a polyurethane prepolymer. Usefulpolyurethane prepolymers are described, for example, in U.S. Pat. Nos.4,131,114; 4,411,262; and 4,502,479, each of which are incorporatedherein by reference. The polyurethane prepolymer may be prepared byreacting one or more polyisocyanates with one or more polyols in anequivalent ratio of from about 2:1 to about 12:1, and preferably fromabout 3:1 to about 5:1 isocyanate groups to hydroxyl groups. Thepolyisocyanate may be aliphatic, cycloaliphatic, or aromaticdiisocyanates, triisocyanates, or tetraisocyanates, as well as biurets,isocyanurates, and similar oligomers of these. Examples of usefulpolyisocyanates include, without limitation, toluene diisocyanates(TDI), including the 2,4 and 2,6 isomers and mixtures of these isomers;diphenylmethane diisocyanates (MDI), including the 4,4', 2,4', and 2,2'isomers and mixtures of these isomers; hydrogenated diphenylmethanediisocyanates, aromatic polyisocyanates derived from phosgenation of thecondensation product of aniline and formaldehyde (polymeric MDI),hexamethylene diisocyanate, isophorone diisocyanate, octamethylenediisocyanate, trimethylhexane diisocyanates, dodecamethylenediisocyanates, cyclopentane diisocyanate, cyclohexane diisocyanate,tetramethylxylene diisocyanate, and biurets, allophonates,isocyanurates, and substituted derivatives of these, such ascarbodiimide-containing polyisocyanates. Preferred among these arepolymeric diphenylmethane diisocyanates (polymeric MDI's).

The polyisocyanate is reacted with at least one polyol. Examples ofsuitable polyols include, without limitation, polyether polyols,polyester polyols including polycaprolactone polyols, and monomericdiols and triols such as 1,6-hexanediol. Preferred polyols includepolyethylene oxide and polypropylene oxide diols and triols,polytetramethylene ether glycols, especially those having a molecularweight of from about 400 to about 2000. Polyalkylene oxide polyols areavailable commercially, for example from BASF Corporation under thetradename Pluracol® and from Union Carbide Corporation under thetradenames Carbowax® and Polyox®.

The prepolymer is preferably mixed with a catalyst. Preferred catalystsinclude tertiary amine catalysts such as tertiary alkanolamines, forexample dimethylethanolamine and dimethylaminodiethyl ether;2,2'-dimorpholinodialkylethers such as 2,2'-dimorpholinodiethylether(DMDEE), available commercially from Texaco, Inc., as Thancat DMDEE; and2,2'-dimorpholinyldialkylethers, such as 4- 2-methyl-2-(4-morpholinyl)ethoxy!-ethyl!morpholine (MEMPE). The catalystis preferably included in amounts of from about 0.1% to about 10% byweight of the impregnating resin mixture.

The curable resin mixture preferably has a viscosity that is low enoughto allow the mixture to enter the pores of the substrate to produce aresin-impregnated substrate, while the viscosity is high enough that asufficient amount remains in the substrate so that upon cure thesubstrate is effectively hardened and good properties are obtained. Theviscosity may be modified according to a variety of obvious means, suchas by addition of low viscosity materials including, without limitation,organic solvents to reduce viscosity or by addition of thickening agentsto increase viscosity. The optimum viscosity may be determined bystraightforward testing. In a preferred embodiment of the invention, theviscosity of the curable resin mixture is from about 5000 to about100,000 centipoise.

The impregnating resin mixture may include other ingredients, such asstabilizers, thickening agents, antifoam agents, pigments or colorants,and so on. Such other additives may be included in minor amounts. Thelubricant impregnated porous substrate is substantially free ofmaterials that would interfere with the properties of the lubricantimpregnated porous substrate as described herein or that would impairthe ability of the lubricant impregnated porous substrate to operate asdesired in the methods of the present invention.

The substrate is impregnated with the curable resin mixture. When acasting substrate is impregnated with curable resin mixture, the weightof the curable resin mixture that is impregnated into the substrate ispreferably from about 30 to about 125% by weight of the substrate.Generally, the resin mixture may flow into the capillary spaces betweenfibers of the fabric.

The invention provides a kit comprising both the lubricant-impregnatedporous substrate and the resin impregnated cast sheet. When the castmaterial is a thermoplastic, water-curable, or air-drying formulation,it is preferred for the cast sheet to be sealed in a compartment of thekit. The lubricant-impregnated substrate may be sealed in the samecompartment as the cast sheet or may be provided in a different sealedcompartment, or (if the lubricant is not volatile) an unsealedcompartment of the same kit. In a preferred embodiment, the lubricant isimpregnated in a towelette, and the towelette is packaged around theoutside circumference of a roll of the cast sheet, thetowelette-encompassed roll being sealed inside of a compartment of thekit. In another preferred embodiment, the lubricant-impregnated sheetand the cast sheet being folded into a single roll, the roll being thensealed inside of a compartment of the kit. In yet a further embodimentof the invention, the lubricant-impregnated sheet and the cast sheet areseparated by a third layer, all three layers being folded into a singleroll and the roll being then sealed inside of a compartment of the kit.In still a further embodiment of the invention, a lubricant-impregnatedporous substrate is placed, and optionally sealed, in one compartment ofthe kit and the cast sheet is sealed inside of a second, separatecompartment of the kit. This final embodiment is particularly preferredwhen the lubricant-impregnated porous substrate is a sponge, pad, orother object of a thickness significantly thicker than the thickness ofthe cast sheet.

The cast sheet or tape that is rolled into the roll of the kit may befrom about 3.5 to about 4.2 yards, preferably from about 4 to about 4.2yards in length and from about 1 to about 10 inches, preferably fromabout 1 to about 5 inches, in width.

The sealing compartments may comprise a peelable layer over a shell of amaterial inert toward both the lubricant-impregnated substrate and thewater-curable resin-impregnated cast sheet. Alternatively, the kit maycomprise foil, foil-lined, plastic, or metallized plastic pouches orcompartments. The kit may further include gloves suitable for wearingduring the cast molding process.

An important aspect of many of the preferred embodiments of the presentinvention is the ability of the person applying the casting material tocontrol the amount of lubricant applied to the gloves during molding ofthe cast, as well as the timing of the application. The lubricant may bereapplied to the gloves by wiping the gloves with the wet toweletteduring forming of the cast and the molding process as necessary.

Using the gloves to which the lubricant has been applied by means of thelubricant-impregnated substrate of the invention, casting tape or sheetis wrapped about the patient's limb, or otherwise applied in multipleadjacent layers The application is assisted by the reduction intackiness of the substrate relative to the gloves without reducingsignificantly the tackiness of the cast substrate relative to itself. Ifthe gloves begin to stick to the cast tape, the wetted sheet, sponge, orpad can be picked up and worked between the gloves in order to depositadditional lubricant onto the glove surfaces. When the desired amountcasting material has been wrapped around the body member, it is oftendesirable to further mold the wrapped cast material about the bodymember. Lubricant may be re-applied from the lubricant-impregnatedporous substrate to the gloves before and during molding the wrappedcast material as desired.

It is also sometimes desirable to use less lubricant prior to and duringapplication of the casting material, so that the tape and packaging canbe easily handled during the wrapping step. Lubricant, or additionallubricant, can then be employed during the molding step.

After application of the casting material is completed, the castingmaterial is allowed to fully harden to form a cast about the wrappedlimb. In one embodiment of the invention, the casting material comprisesa thermoplastic composition that hardens on cooling. In a preferredembodiment of the invention, the casting material comprises a curablecomposition-impregnated sheet, particularly a water-reactive orwater-activated curable composition. In the case of a water-reactive orwater-activated curable composition, the casting material is immersed inwater or otherwise wetted with water prior to applying the castingmaterial around the body member. After the casting material is applied,preferably by wrapping and molding about the body member, the curablecomposition is cured to form the finished cast.

The invention is illustrated by the following examples. The examples aremerely illustrative and do not in any way limit the scope of theinvention as described and claimed. All parts are parts by weight unlessotherwise noted.

EXAMPLES Example 1 Preparation of an Orthopedic Casting Kit

A substrate casting sheet of fiberglass with approximately 10%polypropylene fiber, about 3 inches wide and 4 yards long, havingapproximately 25% stretch, is impregnated with the following mixture:

58 parts by weight Isonate™ 2143L (a diphenylmethane diisocyanate resinavailable from Dow Chemical, Midland, Mich.),

38 parts by weight PPG 725 (a polypropylene glycol available from ArcoChemical Co., Charlotte, N.C.),

2.4 parts by weight dimorpholinodiethyl ether catalyst (available fromHuntsman Corp., Houston, Tex.),

0.1 parts by weight benzoyl chloride (available from Aldrich, Milwaukee,Wis.), and

0.3 parts by weight of silicone 200 fluid (35,000 centipoise, availablefrom Dow Corning Corp., Midland, Mich.).

The impregnated casting sheet, 3 inches by 4 yards, is rolled up into aroll.

A towelette of a rectangular (3 inches by 8 inches) piece of 100%polyester brushed tricot fabric, (weight of 2.5 ounces per square yard)is impregnated with a mixture of 98 parts by weight silicone 200 fluid(350 centistokes, available from Dow Corning Corp., Midland, Mich.) and2 parts by weight sodium lauryl sulfate (Supralate M.E., available fromWitco Corp., Houston, Tex.) in a ratio of about 2.75 grams of lubricantmixture per gram of dry fabric. The impregnated fabric is wrapped aroundthe roll of impregnated casting sheet. The wrapped roll is sealed in afoil pouch under nitrogen.

Example 2 Preparation of a Cast Using the Lubricant-ImpregnatedTowelette

The sealed pouch of Example 1 is opened and the orthopedic castingarticle is removed. Using latex gloves, the towelette-covered roll isplaced in water and squeezed twice while underwater. The roll is thentaken out of the water and squeezed to remove excess amounts of water.The towelette covered roll is used to wet both gloves being worn byrolling it between the palm and wiping both palm. The towelette is thenlaid aside and the wrapping process begun.

The casting sheet is next unrolled while wrapping the sheet around thelimb of a mannequin to form a cast. The lubricated gloves prevent theresin from the tape from sticking to the gloves and allow the hands tomove freely in the molding of the cast. The towelette is used tore-apply more lubricant to coat the palms of the gloves as desired.

Example 3 Preparation of an Orthopedic Casting Kit

A towelette of a rectangular (3 inches by 8 inches) piece of 100%polyester brushed tricot fabric, (weight of 2.5 ounces per square yard)is impregnated with a slurry of 98 parts by weight silicone 200 fluid(350 centistokes, available from Dow Corning Corp., Midland, Mich.) and2 parts by weight of 80 mesh polyvinylpyrrolidone (PVP K120, availablefrom ISP Technologies, Wayne, N.J.). The towelette is impregnated in aratio of about 2.8 grams silicone slurry to about 1 gram of fabric. Theimpregnated fabric is wrapped around the roll of impregnated castingsheet prepared according to Example 1. The roll of casting tape hasabout a seven-inch circumference, providing for a half-inch overlap ofthe wrapped towelette. The wrapped roll is sealed in a foil pouch undernitrogen.

The invention has been described in detail with reference to preferredembodiments thereof. It should be understood, however, that variationsand modifications can be made within the spirit and scope of theinvention and of the following claims. In addition, while the inventionhas been described with particular reference to orthopedic casts andmethods for forming the same, it should be understood that the inventivemethods described for controlled lubricant delivery from alubricant-impregnated porous substrate have a broader and more generalapplicability and are useful for molding tacky materials other than theparticular casting materials for orthopedic casts.

What is claimed is:
 1. A method of forming an orthopedic cast,comprising the steps of:(a) providing a lubricant-impregnated poroussubstrate and a casting material; (b) transferring lubricant from thelubricant-impregnated porous substrate to the glove of a gloved hand toform a lubricated glove; (c) applying the casting material around a bodymember using the lubricated glove; and (d) allowing the casting materialto harden to form an orthopedic cast around the body member.
 2. A methodaccording to claim 1, comprising a further step of immersing thelubricant-impregnated porous substrate in water before transferringlubricant to the glove.
 3. A method according to claim 2, wherein thelubricant is transferred to the glove while the lubricant-impregnatedporous substrate is immersed in water.
 4. A method according to claim 1,wherein lubricant is transferred to the glove from thelubricant-impregnated porous substrate more than one time duringapplying the casting material.
 5. A method according to claim 1, whereinthe lubricant comprises a hydrophobic lubricant.
 6. A method accordingto claim 1, wherein the lubricant comprises at least one member selectedfrom the group consisting of silicone fluids, mineral oils, and mixturesthereof.
 7. A method according to claim 1, wherein the lubricantcomprises a mixture of a silicone fluid and a water-soluble orwater-dispersible lubricant.
 8. A method according to claim 1, whereinthe lubricant comprises a mixture of a silicone fluid and a hydrophilicpolymer.
 9. A method according to claim 8, wherein the mixture comprisesfrom about 80 to about 99% of the lubricant.
 10. A method according toclaim 8, wherein the mixture comprises from about 90 to about 99% of thelubricant.
 11. A method according to claim 8, wherein the hydrophilicpolymer is polyvinylpyrrolidone.
 12. A method according to claim 1,wherein the lubricant comprises a member selected from the groupconsisting of water-soluble lubricants, water-dispersible lubricants,and mixtures thereof.
 13. A method according to claim 12, comprising afurther step of wetting the lubricant-impregnated porous substrate withwater before transferring lubricant to the glove.
 14. A method accordingto claim 1, wherein the casting material comprises a thermoplasticcomposition-impregnated sheet.
 15. A method according to claim 1,wherein the casting material comprises a curable composition-impregnatedsheet.
 16. A method according to claim 15, wherein the curablecomposition is selected from the group consisting of UV-curable,air-during, and water-curing compositions, and mixtures thereof.
 17. Amethod according to claim 16, wherein the curable composition is awater-reactive or water-activated curable composition.
 18. A methodaccording to claim 17, comprising the further step of immersing thecurable composition-impregnated sheet in water prior to applying thecasting material around the body member.
 19. A method according to claim18, wherein the step of applying the casting material comprises wrappingthe casting material around the body member and then molding the wrappedcasting material about the body member prior to allowing said castingmaterial to harden.
 20. A method according to claim 18, wherein thelubricant-impregnated porous substrate and the water-activated curablecomposition-impregnated sheet are immersed in water at the same time.21. A method according to claim 18, wherein the lubricant-impregnatedporous substrate and the water-activated curable composition-impregnatedsheet are separately immersed in water.
 22. A method according to claim20, wherein the lubricant-impregnated porous substrate is a sheet and isheld between the glove and the water-activated curablecomposition-impregnated sheet while immersed in water.
 23. A methodaccording to claim 1, wherein the glove comprises natural rubber latex,synthetic rubber, vinyl, nitrile rubber, or mixtures or laminatesthereof.
 24. A method according to claim 1, wherein the porous substratecomprises a material selected from the group consisting of polyamide,polyester, acrylic, and polyester-polyurethane textiles and textileblends.
 25. A method according to claim 1, wherein the porous substrateis selected from the group consisting of sheets, pads, and sponges. 26.A method according to claim 25, wherein the porous substrate is a sheethaving a thickness of less than about 2.5 cm.
 27. A method according toclaim 26, wherein the sheet comprises a knitted or woven textile.
 28. Amethod according to claim 1, wherein the porous substrate comprises asheet of a brushed knit tricot.
 29. A method according to claim 17,wherein the curable composition comprises a member selected from thegroup consisting of water-reactive liquid organometallic compounds,alkoxy silane terminated polyurethane oligomers, andisocyanate-functional prepolymers.
 30. A method according to claim 1,wherein the lubricant is selected from the group consisting of watersoluble or hydrophilic polymers, surfactants and their ionicderivatives, hydrophilic oligomeric diols, hydrophobic gels and oils,motor oils, greases, silicone fluids and silicone oils, and mixturesthereof.
 31. A method according to claim 1, wherein the lubricant isselected from the group consisting of polyethylene oxide homopolymersand copolymers, polyvinyl alcohol, polyvinylpyrrolidone, polyethoxylatedfatty alcohols and their ionic derivatives, mineral oils, vegetableoils, petroiatum, motor oils, silicone fluids, oils, and greases, andmixtures thereof.
 32. A method according to claim 1, wherein thelubricant is selected from the group consisting of silicone fluidshaving viscosities between about 100 and 100,000 centistokes,polyethoxylated fatty alcohols, polyethylene oxide homopolymers andcopolymers, polyvinylpyrrolidone, and mixtures thereof.
 33. Anorthopedic casting kit, comprising a lubricant-impregnated poroussubstrate and a casting material.
 34. An orthopedic casting kitaccording to claim 33, wherein the casting material comprises athermoplastic composition-impregnated sheet.
 35. An orthopedic castingkit according to claim 33, wherein the casting material comprises acurable composition-impregnated sheet.
 36. An orthopedic casting kitaccording to claim 35, wherein the curable composition is awater-reactive or water-activated curable composition.
 37. An orthopediccasting kit according to claim 35, wherein the curable composition isselected from the group consisting of UV-curable, air-curing, andwater-curing compositions, and mixtures thereof.
 38. An orthopediccasting kit according to claim 35, wherein the curable compositioncomprises a member selected from the group consisting of water-reactiveliquid organometallic compounds, alkoxy silane terminated polyurethaneoligomers, and isocyanate-functional prepolymers.
 39. An orthopediccasting kit according to claim 33, further comprising a pair of gloves.40. An orthopedic casting kit according to claim 33, wherein the poroussubstrate comprises a material selected from the group consisting ofpolyamide, polyester, acrylic, and polyester-polyurethane textiles andtextile blends.
 41. An orthopedic casting kit according to claim 33,wherein the porous substrate is selected from the group consisting ofsheets, pads, and sponges.
 42. An orthopedic casting kit according toclaim 33, wherein the porous substrate is a sheet having a thickness ofless than about 2.5 cm.
 43. An orthopedic casting kit according to claim42, wherein the sheet is a knitted or woven textile.
 44. An orthopediccasting kit according to claim 33, wherein the porous substratecomprises a sheet of brushed knit tricot.
 45. An orthopedic casting kitaccording to claim 33, wherein the lubricant comprises a hydrophobiclubricant.
 46. An orthopedic casting kit according to claim 33, whereinthe lubricant comprises at least one member selected from the groupconsisting of silicone fluids, mineral oils, and mixtures thereof. 47.An orthopedic casting kit according to claim 33, wherein the lubricantcomprises a mixture of a silicone fluid and a water-soluble orwater-dispersible lubricant.
 48. An orthopedic casting kit according toclaim 33, wherein the lubricant comprises a mixture of a silicone fluidand a hydrophilic polymer.
 49. An orthopedic casting kit according toclaim 48, wherein the mixture comprises from about 80 to about 99% ofthe lubricant.
 50. An orthopedic casting kit according to claim 48,wherein the mixture comprises from about 90 to about 99% of thelubricant.
 51. An orthopedic casting kit according to claim 47, whereinthe hydrophilic polymer is polyvinylpyrrolidone.
 52. An orthopediccasting kit according to claim 33, wherein the lubricant comprises atleast one member selected from the group consisting of water-solublelubricants, water-dispersible lubricants, and mixtures thereof.
 53. Anorthopedic casting kit according to claim 33, wherein the lubricantcomprises at least one member selected from the group consisting ofwater soluble and hydrophilic polymers, surfactants and their ionicderivatives, hydrophilic oligomeric diols, hydrophobic gels and oils,motor oils, greases, silicone fluids and silicone oils, and mixturesthereof.
 54. An orthopedic casting kit according to claim 33, whereinthe lubricant comprises at least one member selected from the groupconsisting of polyethylene oxide homopolymers and copolymers, polyvinylalcohol, polyvinylpyrrolidone, polyethoxylated fatty alcohols and theirionic derivatives, mineral oils, vegetable oils, petrolatum, motor oils,silicone fluids, oils, and greases, and mixtures thereof.
 55. Anorthopedic casting kit according to claim 33, wherein the lubricantcomprises at least one member selected from the group consisting ofsilicone fluids having viscosities between about 100 and 100,000centistokes, polyethoxylated fatty alcohols, polyethylene oxidehomopolymers and copolymers, polyvinylpyrrolidone, and mixtures thereof.56. An orthopedic casting kit according to claim 35, wherein thelubricant-impregnated porous substrate and the curablecomposition-impregnated sheet are contained in separate compartments.57. An orthopedic casting kit according to claim 35, wherein thelubricant-impregnated porous substrate and the curablecomposition-impregnated sheet are contained in a single compartment. 58.An orthopedic casting kit according to claim 57, wherein thelubricant-impregnated porous substrate is a sheet that is at leastpartially wrapped around the outside of a roll of the curablecomposition-impregnated sheet.
 59. An orthopedic casting kit accordingto claim 57, wherein the lubricant-impregnated porous substrate is asheet that is rolled up with the curable composition-impregnated sheet.60. An orthopedic casting kit according to claim 59, wherein a thirdlayer separates the lubricant-impregnated sheet and the curablecomposition-impregnated sheet.
 61. An orthopedic casting kit accordingto claim 57, wherein said curable composition-impregnated sheet is inthe form of a roll and said lubricant-impregnated substrate is a sheetthat separates adjacent layers of the roll.
 62. An orthopedic castingkit according to claim 57, wherein the lubricant-impregnated substrateand the curable composition-impregnated sheet are separated by a barrierthat is inert toward the curable composition.